[June 16, 2014]WASHINGTON (Reuters) - The No. 2
U.S. diplomat will travel to Vienna this week to take part in talks over
Iran's nuclear program, the State Department said on Sunday.

In a statement, the State Department said Deputy Secretary of
State Bill Burns would be among the U.S. officials taking part in
the latest round of nuclear talks, which include six world powers
and Iran and are scheduled for Monday to Friday.

The participation of Burns, who led secret U.S.-Iranian negotiations
that helped bring about a Nov. 24 interim nuclear agreement between
Iran and the major powers, could signal that the United States is
intensifying efforts to break a logjam in the nuclear talks.

Iran, the United States, Britain, France, Germany, Russia and China
set a July 20 deadline to reach a comprehensive agreement in an
interim deal they reached in Geneva last November.

The latest round of negotiations in Vienna last month ran into
difficulty when it became clear the number of centrifuges Iran wants
to maintain was well beyond what would be acceptable to the West.

Iran says it needs to maintain domestic uranium enrichment
capability to produce fuel for planned nuclear power plants without
having to rely on foreign suppliers.

Some Western officials believe Iran will need many years to build
any nuclear power stations and that its goal in enriching uranium is
to be able to produce material for nuclear bombs, an allegation Iran
denies.

Iranian President Hassan Rouhani urged the world powers on Saturday
to reach a deal with Tehran by the July 20 deadline, arguing that
sanctions meant to restrict its atomic activity had frayed beyond
repair. He said the economic curbs had been softened by his
government's policy of detente and would "not be rebuilt" even if no
deal was reached.